[robocup-small] Looking ahead to RoboCup 2006

[Michael Babish]

I haven't participated in a RoboCup competition since 2002, so my input is
based solely on the online videos and anecdotes from the Cornell team.

I'd like to formally suggest changing the official ball.  The orange golf
ball works very well, but it has the following problems:

1) It is very small, therefore:
     - Local vision would have a tough time identifying the ball
     - Global vision sometimes loses the ball
     - Robots can occlude the ball from the overhead camera
     - It is difficult to strip the ball away from another robot
2) It is very elastic, therefore:
     - It is difficult to control (it can bounce off the robots)
     - It is easy to kick the ball *very* fast

I think that using a larger, less elastic ball might simplify some of the
current problems in the game.  Also, a larger ball would encourage some
local vision strategies.

I recommend using the same orange plastic ball as the RoboCup Dog League. 
Several teams tested this in Fukuoka in 2002, and our robots could control
the ball without modification.  The kicker still worked, although the ball
moved significantly slower.

I think part of the reason the ball went out-of-bounds so often was that
the ball moved far too fast and the robots couldn't control it.  The
larger plastic ball could not be kicked as fast, and therefore the robots
might be able to catch it before it left the field.  Obviously, this
wouldn't solve all of our problems, but I think it would help the
situation significantly.

Michael Babish
Cornell University RoboCup Team
2000, 2001, 2002